code: def response_value_formater(label, label_start, end_signal):
      if isinstance(label, str):
          return label_start + label + end_signal
      elif label is None:
          return ""
      else:
          raise ValueError(
              f"Unknown label type {type(label)}, only str type is supported"
          )
  
file_path: NeMo/nemo/collections/nlp/data/language_modeling/megatron/gpt_sft_chat_dataset.py
imports: import copy
  import torch
  from nemo.collections.common.tokenizers.tokenizer_spec import TokenizerSpec
  from nemo.collections.nlp.data.language_modeling.megatron.gpt_sft_dataset import GPTSFTDataset
  from nemo.utils import logging
label_desc: Use image node_id 5 for calling a global function with example usage: response_value_formater(label, label_start, end_signal) and returns: unknown, str